[SystemZ] Do not install IfConverter pass at -O0

When not optimizing, do not run the IfConverter pass, this makes
debugging more difficult (and causes a testsuite failure in
DebugInfo/unconditional-branch.ll).



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210263 91177308-0d34-0410-b5e6-96231b3b80d8
XFAIL: test/DebugInfo/missing-abstract-variable.ll on s390x as well


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210264 91177308-0d34-0410-b5e6-96231b3b80d8
Add missing const specifier to a const method.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210265 91177308-0d34-0410-b5e6-96231b3b80d8
[asancov] Fix coverage line info some more.

Now it should always point to the opening brace of the function (in
-asan-coverage=1 mode).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210266 91177308-0d34-0410-b5e6-96231b3b80d8